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Net-Zero Energy Case Studies



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  • 1. Architect-Engineer Services Master Planning and Design for 10-year Development at Central Utility Facility (CUF) Presentation for Gulf Coast Green 2013 Net Zero Energy Case Studies Scott West Mechanical Engineer May 2, 2013
  • 2. Best Practice Jacobs is a Registered Provider with The American Institute of Architects Continuing Education Systems (AIA/CES). Credit(s) earned on completion of this program will be reported to AIA/CES for AIA members. Certificates of Completion for both AIA members and non-AIA members are available upon request. This program is registered with AIA/CES for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product. Questions related to specific materials, methods, and services will be addressed at the conclusion of this presentation.
  • 3. Course Description • This session will focus on design and implementation of net zero energy buildings and how they can be turned into an operational reality. Achieving net zero energy buildings is the adopted goal of the AIA 2030 commitment and is often viewed as the standard for climate neutrality for new buildings. Net zero energy buildings offer particular design challenges but are possible in many circumstances with current technology.
  • 4. Learning Objectives • Cover the various definitions of net zero energy and how they apply to high performance projects • Learn how integrative design can help achieve project energy goals • Review net zero energy case studies and share lessons learned • Evaluate the economics of net zero energy building design and construction
  • 5. Why Are We Concerned With Net Zero Energy? • Energy security • Resource conservation • Reduce operating cost • Mitigating climate change • Local environmental impact reduction • Hedge against future energy price volatility
  • 6. Recent Energy Legislation and Federal Leadership in Green Building Practices • EPAct 2005, EISA 2007, EO 13423, EO 13514, Federal Leadership in High Performance and Sustainable Buildings • EO 13514 from Oct. 2009 states in Section 2.g.i: “beginning in 2020 and thereafter, ensuring that all new Federal buildings that enter the planning process are designed to achieve zero-net-energy by 2030”
  • 7. DoD and DOE Partner Up • In 2008 DoD and DOE launched initiative to support net zero energy military installations • Launched collaborative pilot of Marine Corps. base at Miramar • NREL has helped out with NZEI guidance so far • All US military branches addressing net zero energy to varying degrees
  • 8. AIA 2030 Challenge
  • 9. ASHRAE Path to Net Zero Energy
  • 10. Net Zero Energy Definition Type Description Net Zero Site Energy The boundary is the site and the energy is measured annually at the utility meters Net Zero Source Energy The energy is valued at its point of extraction (e.g. the wellhead or the coal mine) Net Zero Energy Cost The credits received on exported energy equals the amount of annual energy bills from utilities Net Zero Energy Emissions The emissions from fossil fuel energy use are offset by renewable energy fed into the grid on an annual basis
  • 11. NREL Paper Goes Into More Depth on Definition
  • 12. Site-Source Energy Factors • NREL – Source Energy & Emission Factors for Energy Use in Buildings – June 2007
  • 13. Net Zero Energy Definition • Source versus site energy • On-site combustion versus all electrical • Treatment of off-site renewable energy generation and carbon offsets • Campus setting versus treatment of individual buildings • Treatment of embodied energy • Division of responsibilities between owners, tenants and utilities
  • 14. Federal Net Zero Energy Definition for DoD
  • 15. Case Studies
  • 16. University of North Texas – Net Zero Lab
  • 17. Green Design Features • Mixed mode ventilation with solar chimney • Rainwater harvesting • Solar PV and thermal • Ground source heat pumps • Radiant underfloor heating and cooling • Energy recovery ventilation • Daylighting
  • 18. Architectural Floor Plan
  • 19. Underfloor Piping Zone Layout
  • 20. They Built It!
  • 21. University of North Texas – Net Zero Lab
  • 22. Little Rock Air Force Base – C-130J Fuels Maintenance Hangar
  • 23. C-130J: Super Hercules
  • 24. Level 1 Layout
  • 25. Level 2 Layout
  • 26. C-130J Fuels Maintenance Hangar • Net zero energy design definition »Includes plug/process loads »Based on site energy, gas use is okay if it is offset on a per Btu basis »Transportation energy use not accounted for • Challenges »FMH require high exhaust and make-up air flow rates »90.1-2007 PRM requires an artificial cooling system in the hangar (this has changed thankfully) »Hangar infiltration is a big concern in heating season
  • 28. Show Model Inputs for all Alternatives Baseline (Appendix G) Current Concept Design (Appendix G) ZNE Proposed Design (Both) Construction Type U-value (Btu/h- ft2-F) SHGC U-value (Btu/h-ft2-F) SHGC U-value (Btu/h-ft2-F) SHGC Wall-CMU 0.085 - 0.085 - 0.045 - Wall - metal 0.085 - 0.085 - 0.0499 - Roof 0.048 - 0.047 - 0.032 - Lobby glazing 0.650 0.250 0.520 0.331 0.520 0.331 Translucent panels 0.650 0.250 0.140 0.190 0.050 0.150 Door -storefront 0.600 0.250 0.520 0.331 0.520 0.331 Door - Opaque 0.700 - 0.200 - 0.200 - Door- non-swinging 1.450 - 1.450 - 1.450 - Partition Wall 0.123 - 0.094 - 0.094 - Space Classification Cooling SADB Heating SADB RH % Admin Areas 76 68 50 Shops/Storage 76 68 50 Mech/Elect 85 55 50 Comms 75 75 50 Hangar Area (conditioned) 85 65 50 Hangar Area (unconditioned) 110 65 50
  • 29. ECM Energy Savings 0 100 200 300 400 500 600 700 ECM Energy Savings (MWh) Solar Thermal Alternate Ventilation Method Ground Loop - VRF in central core Solar Hot Water Heater Hanger Door Decreased Infiltration Biomass Furnace for Hangar Heating Air-cooled VRF in Central Core Overhangs on Kalwall Panels Increased Insulation Exterior Lighting LED's LED fixtures in the Central core area Standard Kalwall Daylighting Kalwall Aerogel+Daylighting LED lighting in Hanger ECM Bar Charts
  • 30. ECM LEED % Savings -1.00 0.00 1.00 2.00 3.00 4.00 5.00 6.00 ECM LEED Savings % Solar Thermal Alternate Ventilation Method Ground Loop - VRF in central core Solar Hot Water Heater Hanger Door Decreased Infiltration Biomass Furnace for Hangar Heating Air-cooled VRF in Central Core Overhangs on Kalwall Panels Increased Insulation Exterior Lighting LED's LED fixtures in the Central core area Standard Kalwall Daylighting Kalwall Aerogel+Daylighting LED lighting in Hanger ECM Bar Charts
  • 31. Be sure you know your project goals Total Energy Use - Appendix G Models 0 200 400 600 800 1,000 1,200 1,400 1,600 EnergyUse(MWh) Current Concept Design NZE Proposed Design % Improvement over Baseline - Appendix G Models 20 25 30 35 40 45 50 55 60 65 70 %Improvement Current Concept Design NZE Proposed Design
  • 32. Annual Energy Costs - Appendix G Models 0 20,000 40,000 60,000 80,000 100,000 120,000 140,000 160,000 180,000 200,000 Baseline (Appendix G) Current Concept Design (Appendix G) NZE Proposed Design (Appendix G) EnergyCosts($) Domestic Hot Water Heating - Gas Heating - Electric Fan Equipment Cooling Equipment Process Loads Lights Presenting Overall Energy Results
  • 33. Renewable Energy Options
  • 34. Solar PV Array
  • 35. Lessons Learned
  • 36. Look for the Sweet Spot • Delivers the ideal result for clients’ pocket books, the environment and society ECONOMY SOCIETY ENVIRONMENT Sustainable Development (the ‘sweet spot’) Viable Bearable Equitable
  • 37. Integrated (Integrative) Design Process
  • 38. Conceptual Project Planning Design Team City / County Building Owner Energy Consultant Building Occupants Cx Agent Project Manager Utility Company 3rd Party Engineers & Inspectors MEP Engineers Interior Designer Architect Landscape Architect Sustainable design is most effective when applied at the earliest stages of design The conceptual design process is a collaboration of several disciplines that effectively integrates all aspects of site planning, building design, construction, operations and maintenance A Sustainability (Eco) Charrette is an intensive workshop in which stakeholders and experts come together to address project sustainability issues The Charrette should result in unified sustainability, design and construction goals for everyone to work toward
  • 39. A Sense of Place • Integrate the building with its surroundings • Apply the most economical options to achieve the desired result (e.g. don’t install a wind turbine to look green that won’t be running most of the time!) • Passive solar design should not be skipped over but should be balanced with functionality and aesthetics
  • 40. NZE Hierarchy
  • 41. NZE Design for Passive Measures • There is an economical limit to insulation levels (diminishing returns) • Limiting solar heat gain through high performance glazing or solar shading is paramount (especially in Texas!) • If your local climate is amenable to natural ventilation, the architectural design should be accomodating to it, we have the tools now! • Good daylight design is an iterative process and proper modeling time should be allotted
  • 42. NZE Design for HVAC • Variable refrigerant flow (VRF) – very cost- effective now compared to traditional systems • Geothermal • Radiant heating/cooling • Displacement ventilation (and sometimes UFAD) • Energy recovery ventilation – decouple space conditioning from ventilation load to improve effectiveness and control • Use LED lighting where you can and use lighting controls wherever they will help, e.g. occupancy and daylight sensing
  • 43. NZE Design for Renewables • Solar PV – Very “plug-and-play” but account for placement and orientation, PPA is a popular vehicle for large installations, default NZE equalizer • Solar thermal – EISA 2007 requirement for federal buildings, usually a no-brainer for NZE • Transpired solar collectors – excellent for areas with simultaneous sunshine and heating hours • Biomass – difficult to beat as a high quality heat source • Wind – often very cost-effective but hub height must be high enough, very visible though • Offshore wind and wave/current energy – good potential for coastal areas
  • 44. NZE for Designers • Form follows function instead of function following form, NZE is a performance target and deviating from this principle can torpedo an otherwise successful approach • Integrated, coordinated approach: disciplines should not work in isolation, design changes can have effects all the way down the line • Model energy use early and often • Design with a “systems mentality”; like in nature all building systems are somehow connected, e.g. DHW on geothermal system, selection of material reflectances affects daylighting, etc.
  • 45. NZE for Building Users/Owners • Plug/process loads become 40% or higher of overall building energy use for NZE designs • Occupant behavior’s effect on energy use becomes very significant, behavioral change is often necessary • Emphasis on flexibility rather than recipe approach: Might have to revisit existing design standards and decisions in order to achieve goal of NZE • Suggest energy sub-metering, EMS and dash-boarding to complete energy information feedback loop • Expect to spend more time on conceptual design phases
  • 46. Cost of Net Zero Energy • Cost premium anywhere between 5% up to 25% or even higher • Emphasis on delivering NZE economically • Rigorous life cycle costing is crucial • Implementing passive energy measures can often down-size HVAC equipment enough to save significant costs • Spend time on careful cost estimation at various decision points: rules of thumb and $/sf estimates don’t work very well for NZE
  • 47. Net Zero Energy Economics • How effective is the energy reduction measure compared to PV? • For the same amount of kWh saved from an ECM, how does it compare to the cost of PV to generate the same amount of kWh? • This is often the cost inflection point between energy efficiency and renewable energy
  • 48. Thank you Scott West, P.E. Mechanical Engineer T: 281.776.2507 Quest ions
  • 49. Bibliography 1. US Army Vision for Net Zero: 2. Architecture 2030 Challenge: 3. ASHRAE; Report of the Technology Council Ad Hoc Committee on Energy Targets; June 2010 4. 7 Group, Bill Reed; The Integrative Design Guide to Green Building; 2009